The 1991 RGV250 delivers yet more race track technology to
the road/David Lancaster

hen someone, somewhere, comes to look back on the 1980s with
some degree of hindsight, they might find themselves looking rather closely at
the 250 class. Closer than some would have predicted. The capacity that new
legislation threatened to kill off has survived a few lean years, and now makes
young men and women drool at the sight of the latest hot kit from Japan. But
what is more interesting perhaps is the technological battlefield the class has
become. Freed from the public-spirited, legislation-conscious pressures that
larger capacities have to live under, the 250s of today can, well, go balls-out
for speed and handling without hindrance.

And that's exactly what they're doing. Suzuki's new RGV250M
marks another step towards two-stroke perfection. It cocks a snoot, yet again,
at the big-bore obsessed among us who ring this and other offices complaining
that their ZZ-R1100 'needs more power...' and it shows that for single-purpose
riding, a 250 can supply as much fun as any other capacity. Finally, it shows
that gull-arm swingarms and inverted forks are more than mere fashion
statements. That doesn't stop them from being the latest trendy paddock wear
though, which they undoubtedly are.

With fairly major engine revisions dealt with last year, Suzuki
have decided to concentrate instead on a few tweaked electronic gizmos and
creating a chassis that is nearly up to GP standards. The bike's closest
competition, Kawasaki's KR1-S, just won the votes of road and proddie racers
last year due to its greater power and more complete chassis. The RGV looked the
biz, and behaved near perfectly, but a slight delay and notchiness in the
gearchange and equally slight sloppiness at the front prevented it being the
outright winner. Everything is slight in this sector; the competition is very
close, closer even than in other classes. This may well be a function of the
manufacturer's single-minded quest for speed which is, largely, absent in other
capacity with trifles such as pillion comfort and luggage capacity to consider.

This year's RGV250, then, gets upside down forks and a so-called
gull-wing swing arm. Some debate centres on the correct term for this new
species of rear swingarm. Suzuki call theirs a Call-Box swingarm -Crescent
Aluminium Box, of course. Honda, it is believed, go for Gull-Arm. But gulls
don't have arms. Another term finding some favour - or should it be flavour? -
is banana swingarm, but somehow this would seem a too frivolous label for such a
neat piece of kit, and anyway, there wasn't a banana in sight at Misano where
the RGV was launched. I looked. Personally, I take my cue from two things:
first, it does look like a gull's wing. But if that isn't enough for you, the
sporting minded under-thirties among you (that's Tom out) may recall a type of
skateboard truck popular, and expensive, in the late 70s - the Gull-Wing. This
would seem to end the debate as far as we're concerned.

Fashion statements they maybe, but they have undoubtedly wrought
more than superficial benefits. Suzuki claim, and who are we to disbelieve them,
that the upside downies give 33 per cent greater 'flexural stability' and 30 per
cent greater 'torsional' rigidity. The gull-wing swingarm makes way for the twin
exhaust pipes which now run up

the same side of the RGV so reasonable ground clearance is thus
maintained with better routing. The pressed single unit construction item also
allows an enlarged section of swingarm to be deployed, so increasing rigidity.
What more excuse could you want for wearing flares?

On the road, well, race track, the improvement is immediately
noticeable. This is one solid little bike. Up front the slightly altered size
tyre (110/70 compared to last year's 110/60, still a 17 incher) would seem to
have helped things, but most of the credit must go to those upside down forks.
They boast a full 120mm of travel which the now 300mm disc brakes use to the
full. But stability and steering input are maintained even under the heaviest
braking input or turning force. The back's improvement is less obvious; but the
rod and bell Link-type system absorbs road irregularities and acceleration
without a worry. On the standard set-up - characteristically soft -you can feel
things working fore and aft, but this is called feedback. The four-piston
calipers on those massive floating discs ask a lot of such a small bike. But
they give as much in return with heaps of feel and power. The 250 can be braked
until the front tyre screams in protest without anything getting unsettled; it
can be braked into and in a corner and only in the last instance does the
transference of forces have any down-side.

With the powerband as narrow as ever, you have to be sure that
the needle is suitably placed on the rev-counter for the drive to be there when
it's needed. It won't drop-in on a corner dramatically, nor will it run straight
on without the power to keep it on line. All it'll do is lose you some momentum
which, however, is crucial to the RGV because there isn't the torque to get you
out of trouble if you're in the wrong gear. Nevertheless power comes in a usable
form at just over four thousand revs, and starts to get exciting at around seven
grand. Peak power, a claimed 61 hp, is at 11 .000 rpm

But what would you expect a from a 249cc crankcase induced
V-twin two-stroke? Nothing major has changed in the basic measurements of the
RGV with the bore remaining at 56mm and the stroke 50.6mm. Compression ratio is
however now lower at 7.3:1. The 180 degree crank is still in place along with
the six-speed box but second, fourth, fifth and sixth gears use different
ratios. However, the rear of the exhaust pipes is less convoluted in its
pattern, so improving gas flow efficacy. The improved mid-range response and
wider power band come about mainly from this and work to the ignition and timing
mechanisms. Suzuki's Advanced Power Control (SAPC), apart from being one of just
three acronyms the RGV sports, endeavours to control the twin cylinder engine
running with help from AETC-II and MDIS. These stand - come on, bear with me,
someone out there must want to know - for Automatic Exhaust Timing Control and
Multiple Digital Ignition System. Engine revolutions and throttle openings are
monitored through two branches of the air passage the twin 34mm Mikuni
Slingshots:

a main one, utilising a valve with stepless air intake control,
and a pilot route, with a new on/off valve control for much closer regulation.
At the top end the exhaust timing also watches rpm through a sensor, but with
the help of a valve just back of the exhaust port. The new AETC system -hence
the II - has three stages of timing control, over last year's two. The AETC has
settings for high, medium and low and varies timing accordingly for most
efficiency and, it is hoped, better mid-range power.

To cap all this is the MDIS which also monitors rpm and throttle
openings and alters the ignition to suit by reference to a memory of the best
ignition timing for each set of circumstances. The cunning little thing can even
detect whether you're running an opening, closing or trailing throttle - all at
the same rpm. What all this adds up to is a plethora of electronic systems
which, by any other name, would be called engine management. Nothing is private
and it's difficult to imagine outwitting the bike. The rev cut-out, at
12,500rpm, further alerts you to this dividing up of the power stakes. The
RGV250 may be an increasingly easier bike to ride, but this owes everything to a
development plan of ever baffling sophistication.

But will little Johnny or Janie care when they throw their eager
legs over the latest hot 250? I doubt it. What they'll find is a bike which
wears all the latest gear, wider tyres than last year, a claimed increase in
power to 61 hp and brakes that make stopping as much fun as accelerating. It's
also a lot smoother in operation at the gearbox where a coaxial gearshift uses
needle roller bearings to smooth things out. The coaxiality comes from the shift
lever being located along the line as the footpeg which ensures a cleaner,
easier, gear change. This alteration makes the RGV a bike with a beautifully
slick gear engagement. The increased mid-range makes this only a slightly less
called for performance, but you still have to play the gearbox. Still, when you
think of the amount of power that's been extracted from a 250 - top speed
reached on the back straight of Misano was an indicated 130mph, with probably a
little more to come - it is a drivable bike. All things are relative, and it's
better than last year's bike on first impressions.

On a circuit like Misano where lefthanders predominate only a
couple of options are open to the peaky RGV rider. First is the easiest, but not
the fastest. On the tighter bends, of which there are only really two left
handers, a single gear can be used, but the set-up is crucial. Come in on the
power, and the chances are it'll be long gone by the time you exit. Shifting up
a gear on entrance seems strange, but as the track opens, it really is the best
way of keeping bike on line and mind on other things than the impending
rev-limiter. The other option is to shift part way round. The coaxial set-up
certainly smoothes the way for this, but until it's clear exactly how much space
is there on a certain line, there is a risk of running out of ground clearance.
Not with the bike, but with your foot. It needs, indeed it repays, a quick,
definite flick.

Such minutia may seem far removed from everyday riding, and in
one sense it is. Riding the bike at the peak of your abilities is never so
sustained on the road. But knowing when you need to shift up, and where it's
possible, is part of the fun of riding an RGV. With such a stable chassis
liberties can be taken - they frequently were - but the correct gear for a
corner is crucial on the RGV250. Get it wrong, and you'll be pulling too high a
ratio with the subdued wail of the pipes long gone behind you or swearing at the
rev-limiter for cutting in, or at yourself for not watching the tacho.

So, the quarter-litre bike is still challenging to ride. The
riding position does nothing to alter this. There's no pretence at being
anything other than a racer on the roads; the blurb tells us that the RGV250 has
'proportions derived directly from the RGV Gamma' - the factory race bike. It
feels like it too. The bars are low, the pegs are high and the seat minimal.
It's not comfortable, even when ridden hard, and even the smooth clutch and
brake levers can't save it from being what it is - a backside in the air,
short-hop bike. Still, the mirrors are effective as well as being suitably
minimalist... the same goes for the new double tailight section. The detailing
throughout is damn good, from the remote reservoir at the rear to the intricate
mounting of the front brake fluid reservoir on the bars.

The improvements made to the RGV250 tell of Suzuki's continued
dedication to both the bike and the class. While the engine management system
undoubtedly contains some very trick stuff, and this stuff makes for a smoother,
better running unit, it's on the chassis side that things have really moved.
With the standard of both the RGV and the KR1-S it's difficult to say it now
handles/steers/brakes better - neither bike did those things badly last year.
Where the changes might tell is in how far you can adjust your RGV to suit your
own tastes. We weren't able to play much with the settings in Misano, but a
brief foray with a increased preload setting at the front showed only that
there's lots to play with; most of it, I suspect, without any penalty in terms
of performance. Only time will tell. The upside down forks are more than mere
gimmick, especially on a bike like the RGV.

Why? Because steering and braking are so important to this bike;
the power is good, but nowhere near breathtaking, so the little Suzuki makes
ground up through brakes which are among the best in the business, and light,
sensitive steering. There's a hint of oversteer evident, but otherwise the setup
is completely neutral. The range of preload, rebound, and compression adjustment
is phenomenal. Not only is the degree and rate of travel adjustable, but with
this amount of adjustment, braking and steering behaviour too. The RGV's rake of
25 degrees is a little down on last year's 26, the trail shrunk by 4mm to 94mm.

In the final analysis the RGV250M, available in either black or
blue/white this year, can only really be judged against its nearest rival, the
Kawasaki. Preferably on a race track. The RGV steals a lot of ground with its
trick suspension and wacky swingarm though. The aluminium-alloy double cradle
frame has gained rounder edges (for better aerodynamics, it says here) but
otherwise is unchanged. Wheels have grown slightly, the radiator has changed
shape, and bolt-on seat rails make maintenance easier, but it's the smooth flow
of the Gull-Wing and meaty appeal of the inverted forks which'll win friends and
influence people. Suzuki have once again shown that what was, only a couple of
years ago, the preserve of a select few to thrash around the circuits of the
world can now be yours to do what you will with. Suggestions as to what to do
with a Gull-Wing on a postcard please.

Source Cycle 1991

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